The present invention relates to magnetic tape cassettes in general and more particularly to a magnetic tape cassette hub having a hub body member with improved tape retention means.
In a conventional magnetic tape cassette, there is provided a pair of rotatable magnetic tape hubs which serve periodically and successively as a supply and take-up reel for magnetic tape contained in the cassette. In contrast to an endless-loop tape cartridge there is required in each of the hubs of a cassette a means for securing an end of the tape to the hub. The requirement is such that the tape will not separate from the hub even under the severe high-speed conditions encountered when the tape is re-wound from one hub to the other.
Since the early stages of cassette fabrication, a plug-like member has been provided for securing tape to a hub body member. In a typical application, the plug is press fitted into a cavity provided in a peripheral wall portion of the hub body member. When the tape is inserted in the hub, a free end is threaded about the plug-like member and held in the cavity by means of the compressive forces set up between the member and the walls of the cavity. A portion of the free end of the tape, called a "pig-tail", is generally left dangling beyond the edge of the plug at the point where the free end of the tape egresses from the cavity. In many instances, due to the difficulty of cutting and removing the pigtail, a manufacturer will not cut the pig-tail. The pig-tail can then cause a non-uniform radius in the pack resulting at times in permanent physical damage to the tape. Even when the pig-tail is cut frequently, the severed portion is left loose and may stay on the hub assembly from static electricity and later on get wound up in the tape pack. This may result, during tape take-up, in a tape pack of non-uniform radius which may, and frequently does, adversely affect speed control, reproduction or other cassette operating characteristics.
As an alternative, an approach which has been used to eliminate the problems associated with the pigtail has included using a pivotable latching member to secure tape to a hub. In this approach, a cavity is provided in a wall portion of a hub body member for receiving the latching member. The cavity and the latching member are provided with one or more male-female members between which the end of the tape is threaded and captured. The free end of the latching member is provided with a catch or locking means for engaging a portion of a side wall of the cavity. When the latching member is engaged, the male-female members are compressed into interlocking engagement for retaining the tape therebetween.
However, with the increased use of tape and hub materials of very low coefficients of friction, the prior known tape retention apparatus, including those which eliminate pig-tail problems, have proved to be less than satisfactory in their inability to retain such tape.